CT Radiation Dose Reduction With Preserved Diagnostic Performance: How Far Have We Come Over 25 Years?

Concerns about the risk of radiation from CT have driven a spectrum of major advances in radiation dose reduction technology since the 2000s, including added beam filtration, dynamic z-axis collimation, automatic tube current modulation and tube potential selection, advanced iterative reconstruction, and deep learning-based reconstructions. The introduction of photon-counting detector CT further improved dose efficiency through electronic noise rejection, optimal photon-energy weighting, and high-resolution data acquisition. This Review summarizes key milestones and technologic innovations that have led to substantial reductions in CT radiation doses and provides examples of the cumulative impact of these advances on CT doses and image quality for routine examinations in various anatomic sites. This article also highlights the importance of an objective task-based image quality assessment to ensure that diagnostic performance is not compromised as dose is reduced, particularly for emerging deep-learning-based reconstruction and postprocessing noise reduction methods.